To develop an age-dependent mathematical model of the isolated ex-vivo human crystalline lens shape to serve as basis for use in computational modeling.

This study aimed to quantify biometric modifications of the anterior segment (AS) during accommodation and to compare them against changes in both accommodative demand and response. Thirty adults, aged 18-25 years were rendered functionally emmetropic with contact lenses. AS optical coherence tomography (AS-OCT) images were captured along the 180° meridian (Visante, Zeiss Meditec, Jena, Germany) under stimulated accommodative demands (0-4 D). Images were analysed and lens thickness (LT) was measured, applying a refractive index correction of 1.00. Accommodative responses were also measured sequentially through a Badal optical system fitted to an autorefractor (Shin Nippon NVision-K 5001, Rexxam, Japan). Data were compared with Dubbelman schematic eye calculations. Significant changes occurred in LT, anterior chamber depth (ACD), lens centroid (i.e., ACD + LT/2), and AS length (ASL = ACD + LT) with accommodation (all p < 0.01). There was no significant change in CT with accommodation (p = 0.81). Measured CT, ACD, and lens centroid values were similar to Dubbelman modelled parameters, however AS-OCT overestimated LT and ASL. As expected, the accommodative response was less than the demand. Interestingly, up until approximately 1.5 D of response (2.0 D demand), the anterior crystalline lens surface appears to be the primary correlate. Beyond this point, the posterior lens surface moves posteriorly resulting in an over-all sigmoidal trajectory. he posterior crystalline lens surface demonstrates a sigmoidal response with increasing accommodative effort.

To optimize our in vivo magnetic resonance imaging (MRI)-based optical model of the human crystalline lens, developed with a small group of young adults, for a larger cohort spanning a wider age range.

Cycloplegics have been reported to induce changes in the lens thickness. However, the studies of correlation between cycloplegia and the lens position are limited. This study aims to investigate changes in crystalline lens rise (CLR) and other anterior segment parameters after inducing cycloplegia with tropicamide.

Actin and myosin within the crystalline lens maintain the structural integrity of lens fiber cells and form a hexagonal lattice cradling the posterior surface of the lens. The actomyosin network was pharmacologically disrupted to examine the effects on lenticular biomechanics and optical quality.

The idea of transplanting a sheet of laboratory-grown corneal endothelium dates back to 1978; however, the ideal scaffold is still lacking. We hypothesized that human crystalline lens capsules (LCs) could qualify as a scaffold and aimed to characterize the properties of this material for endothelial tissue engineering. LCs were isolated from donor eyes, stored at -80 °C, and decellularized with water and trypsin-EDTA. The decellularization was investigated by nuclear staining and counting and the capsule thickness was determined by optical coherence tomography and compared with Descemet's membrane (DM). Transparency was examined by spectrometry, and collagenase degradation was performed to evaluate its resistance to degradation. Cell-scaffold interaction was assessed by measuring focal adhesions surface area on LC and plastic. Finally, primary corneal endothelial cells were grown on LCs to validate the phenotype. Trypsin-EDTA decellularized most effectively, removing 99% of cells. The mean LC thickness was 35.76 ± 0.43 μm, whereas DM measured 25.93 ± 0.26 μm (p < .0001). Light transmission was 90% for both LC and DM. On a collagenase challenge, LC and amniotic membrane were digested after 13 hr, whereas DM was digested after 17 hr. The surface area of focal adhesions for cells grown on coated LCs was at least double that compared with other conditions, whereas tight junctions, ion pumps, and hexagonal morphology were well maintained when endothelial cells were cultured on LCs. In conclusion, LCs demonstrate excellent scaffolding properties for tissue engineering and sustain the cell phenotype and can be considered a suitable substrate for ocular tissue engineering or as a template for future scaffolds.

We quantify the posterior surface distortions in optical coherence tomography (OCT) images of isolated crystalline lenses. The posterior radius of curvature and asphericity obtained from OCT images acquired with the beam incident first on the anterior, and then the posterior, surface were compared. The results were compared with predictions of a ray-tracing model which includes the index gradient. The results show that the error in the radius of curvature is within the measurement reproducibility and that it can be corrected by assuming a uniform refractive index. However, accurate asphericity values require a correction algorithm that takes into account the gradient.

To quantitatively analyze changes in the inner components of the human crystalline lens during accommodation in adults. Eyes of 23 subjects were sequentially examined using CASIA2 Optical Coherence Tomography under 0D, - 3D and - 6D accommodation states. The anterior chamber depth (ACD), anterior and posterior crystalline lens radius of the curvature (ALRC and PLRC) were obtained using built-in software. The lens thickness (LT), lenticular nucleus thickness (NT), anterior cortex thickness (ACT), posterior cortex thickness (PCT), anterior and posterior lenticular nucleus radius of the curvature (ANRC and PNRC), anterior and posterior lenticular nucleus vertex (ANV and PNV) were quantified manually with the Image-pro plus software. During accommodation, the ACD became significantly shallower and LT significantly increased. For changes in the lens, the ALRC decreased by an average magnitude (related to accommodative stimuli) 0.44 mm/D, and PLRC decreased 0.09 mm/D. There was no difference for the ACT and PCT in different accommodation states. For lenticular nucleus response, NT increased on average by 30 μm/D. Both the ANRC and PNRC decreased on average by 212 μm/D and 115 μm/D respectively. The ANV moved forward on average by 0.07 mm under - 3D accommodative stimuli and 0.16 mm for - 6D. However, there was no statistically significant difference between different accommodation states in the PNV movement. Under accommodation stimulation, lens thickness changed mainly due to the lenticular nucleus, but not the cortex. For the lenticular nucleus, both the ANRC and PNRC decreased and ANRC changed the most. The anterior surface of the nucleus moved forward while the posterior surface of the nucleus moved backward but only slightly.

To report calculated crystalline lens power and describe the distribution of ocular biometry and its association with refractive error in older Chinese adults.

The lenticular fiber cells are comprised of extremely long-lived proteins while still maintaining an active biochemical state. Dysregulation of these activities has been implicated in diseases such as age-related cataracts. However, the lenticular protein dynamics underlying health and disease is unclear. We sought to measure the global protein turnover rates in the eye using nitrogen-15 labeling of mice and mass spectrometry. We measured the 14N/15N-peptide ratios of 248 lens proteins, including Crystallin, Aquaporin, Collagen and enzymes that catalyze glycolysis and oxidation/reduction reactions. Direct comparison of lens cortex versus nucleus revealed little or no 15N-protein contents in most nuclear proteins, while there were a broad range of 14N/15N ratios in cortex proteins. Unexpectedly, like Crystallins, many enzymes with relatively high abundance in nucleus were also exceedingly long-lived. The slow replacement of these enzymes in spite of young age of mice suggests their potential roles in age-related metabolic changes in the lens.

While many studies investigate the cytoskeletal properties of the lens with respect to cataract development, examinations of how these molecular structures interact are few. Myosin light chain kinase (MLCK), actin, and myosin are present on the crystalline lenses of chickens. The purpose of this experiment was to determine whether contractile proteins found on the lens play a role in the optical functions of the lens at rest, and during accommodation.

To measure the crystalline lens tilt in eyes with various degrees of myopia before cataract surgery using swept-source optical coherence tomography (SS-OCT).

To investigate crystalline lens tilt and decentration with respect to the corneal vertex (CV) using swept-source optical coherence tomography (SS-OCT) combined with three-dimensional (3D) reconstruction.

The prevalence of nuclear cataracts was observed to be significantly higher among residents of tropical and subtropical regions compared to those of temperate and subarctic regions. We hypothesized that elevated environmental temperatures may pose a risk of nuclear cataract development. The results of our in silico simulation revealed that in temperate and tropical regions, the human lens temperature ranges from 35.0 °C to 37.5 °C depending on the environmental temperature. The medium temperature changes during the replacement regularly in the cell culture experiment were carefully monitored using a sensor connected to a thermometer and showed a decrease of 1.9 °C, 3.0 °C, 1.7 °C, and 0.1 °C, after 5 min when setting the temperature of the heat plate device at 35.0 °C, 37.5 °C, 40.0 °C, and 42.5 °C, respectively. In the newly created immortalized human lens epithelial cell line clone NY2 (iHLEC-NY2), the amounts of RNA synthesis of αA crystallin, protein expression, and amyloid β (Aβ)1-40 secreted into the medium were increased at the culture temperature of 37.5 °C compared to 35.0 °C. In short-term culture experiments, the secretion of Aβ1-40 observed in cataracts was increased at 37.5 °C compared to 35.0 °C, suggesting that the long-term exposure to a high-temperature environment may increase the risk of cataracts.

There is a great need for accurate biometric data on human lenses. To meet this, a compact tabletop optical comparator, the minishadowgraph, was built for measuring isolated eye lens shape and dimensions while the lens was fully immersed in supporting medium. The instrument was based around a specially designed cell and an illumination system which permitted image recording in both sagittal and equatorial (coronal) directions. Data were acquired with a digital camera and analyzed using a specially written MATLAB program as well as by manual measurements in image analysis software. The possible effect of lens orientation and gravity on the dimensions was examined by measuring dimensions with anterior or posterior surfaces up and by measuring lenses with calipers after removal from the minishadowgraph cell. Dimensions, curvatures and shape factors were obtained for 134 fully accommodated lenses ranging in age from birth to 88 years postnatal. Of these, 41 were from donors aged under 20 years, ages which are generally of limited availability. Thickness and diameter showed the same age-related trends described in previous studies but, for the lenses measured in air, age-dependent differences were observed in thickness (-5 to 0%) and diameter (+5 to 0%), consistent with gravitational sag. Anterior and posterior radii of curvature of the central 3 or 6 mm, depending on lens diameter, increase with age, with the anterior increase greater than the posterior. The anterior surface shape of the neonatal lens is that of a prolate ellipse and the posterior, an oblate ellipse. Both surfaces become hyperbolic after age 20. The data presented here on dimensions, shape and sagging will be of great value in assessing age-related changes in the optical and mechanical performance of the lens. In particular, the comprehensive data set from donors aged under 20 years provides a unique and valuable insight to the changes in size and shape during the early dynamic growth period of the lens.

Lens transparency depends on the accumulation of massive quantities (600-800 mg/ml) of twelve primary crystallines and two truncated crystallines in highly elongated "fiber" cells. Despite numerous studies, major unanswered questions are how this heterogeneous group of proteins becomes organized to bestow the lens with its unique optical properties and how it changes during cataract formation. Using novel methods based on conical tomography and labeling with antibody/gold conjugates, we have profiled the 3D-distribution of the αA-crystalline in rat lenses at ∼2 nm resolutions and three-dimensions. Analysis of tomograms calculated from lenses labeled with anti-αA-crystalline and gold particles (∼3 nm and ∼7 nm diameter) revealed geometric patterns shaped as lines, isosceles triangles and polyhedrons. A Gaussian distribution centered at ∼7.5 nm fitted the distances between the ∼3 nm diameter gold conjugates. A Gaussian distribution centered at ∼14 nm fitted the Euclidian distances between the smaller and the larger gold particles and another Gaussian at 21-24 nm the distances between the larger particles. Independent of their diameters, tethers of 14-17 nm in length connected files of gold particles to thin filaments or clusters to ∼15 nm diameter "beads." We used the information gathered from tomograms of labeled lenses to determine the distribution of the αA-crystalline in unlabeled lenses. We found that αA-crystalline monomers spaced ∼7 nm or αA-crystalline dimers spaced ∼15 nm center-to-center apart decorated thin filaments of the lens cytoskeleton. It thus seems likely that lost or gain of long-range order determines the 3D-structure of the fiber cell and possible also cataract formation.

BACKGROUND The aim of this study was to present ophthalmological findings regarding Alport syndrome and report refractometry data and to present possible early signs of the syndrome. MATERIAL AND METHODS Seven patients suffering from Alport syndrome were referred to the Department of Ophthalmology at the University of Debrecen between January 1st, 2014, and December 31st, 2015. All patients underwent slit lamp evaluation and dilated fundus biomicroscopy, with special attention paid to lenticonus and retinal changes. IOL Master, Pentacam HR, and ultrasound biomicroscopy were performed to assess keratometry, corneal thickness, anterior chamber depth, lens size, and axial length data. RESULTS One patient out of seven had ocular symptoms. Posterior polymorphous corneal dystrophy (PPMD) and dot-and-fleck retinopathy were seen. Meanwhile, although keratoconus was not proven, remarkable astigmatism with high myopia was detected. The other six patients were found to have a significantly smaller lens diameter (an average of 7.82±0.66 mm, p=0.035) compared to normal controls (an average of 8.65±0.46 mm). Lenses also tended to be thicker in Alport patients (3.48±0.19 mm) compared to controls (3.4±0.2 mm), although the difference was not significant (p=0.394). The power of the lens also showed a significant difference (p=0.026), with Alport patients having lower lens power. CONCLUSIONS Alport syndrome patients without classical ophthalmological findings have smaller crystalline lens diameter and lower lens power. These signs may support the diagnosis of Alport syndrome. Ophthalmologists should not only seek for the known classic signs, but also the parameters of the crystalline lens, especially if genetic testing is not available.

The strong facet-dependent performance of glass-supported CeO2 thin films in different applications (catalysis, smart windows, etc.) has been the target of diverse fundamental and technological approaches. However, the design of accurate, cost-effective and scalable methods with the potential for large-area coverage that produce highly textured glass-supported CeO2 thin films remains a technological challenge. In the present work, it is demonstrated that under proper tuning conditions, the ultrasonic spray pyrolysis technique enables one to obtain glass-supported polycrystalline CeO2 films with noticeable texture along both the (100) and (111) directions, as well as with randomly oriented crystallites (no texture). The influence of flow rates, solution molarity, and substrate temperature on the texture and morphological characteristics, as well as optical absorption and Raman response of the deposited films, is evaluated. The obtained results are discussed on the basis of the combined dependence of the CeO2-exposed surfaces on the thermodynamic stability of the corresponding facets and the reaction kinetics, which modulate the crystallite growth direction.

Preventing or delaying the onset of presbyopia and cataract formation remains a challenge. The goal of this study was to establish the utility of the Vision Index Pen (VIP), designed to measure in vivo dynamic light scattering (DLS) from the crystalline lens, in the detection of early cataract or loss of accommodation and to show reproducibility through trials at two independent sites. The gradual loss of transparency of the lens was characterized by the lens crystallin aggregation index (LCX) derived from measured DLS data.

To study correlations of crystalline lens anatomy and position parameters obtained using intraoperative spectral-domain (SD) optical coherence tomography (OCT) in cataract patients.